This study aims at comparing two Italian case studies in relation to schoolchildren’s plate waste and its implications, in terms of nutritional loss, economic cost and carbon footprint.

Plate waste was collected through an aggregate selective weighting method for 39 d.

Children from the first to the fifth grade from four primary schools, two in each case study (Parma and Lucca), were involved.

With respect to the served food, in Parma, the plate waste percentage was lower than in Lucca (P < 0·001). Fruit and side dishes were highly wasted, mostly in Lucca (>50 %). The energy loss of the lunch meals accounted for 26 % (Parma) and 36 % (Lucca). Among nutrients, dietary fibre, folate and vitamin C, Ca and K were lost at most (26–45 %). Overall, after adjusting for plate waste data, most of the lunch menus fell below the national recommendations for energy (50 %, Parma; 79 %, Lucca) and nutrients, particularly for fat (85 %, Parma; 89 %, Lucca). Plate waste was responsible for 19 % (Parma) and 28 % (Lucca) of the carbon footprint associated with the food supplied by the catering service, with starchy food being the most important contributor (52 %, Parma; 47 %, Lucca). Overall, the average cost of plate waste was 1·8 €/kg (Parma) and 2·7 €/kg (Lucca), accounting respectively for 4 % and 10 % of the meal full price.

A re-planning of the school meals service organisation and priorities is needed to decrease the inefficiency of the current system and reduce food waste and its negative consequences.